As shown in FIG. 9, in a conventional magnetic head cleaning system, for example, loading grooves 57, 58 are formed through a chassis 55 by the left side and right side of a rotary drum 56, and pole bases 59, 60 are respectively disposed therein, which can be shifted guided by the respective loading grooves 57, 58. Poles 61, 62 are respectively secured to the pole bases 59, 60.
At a vicinity of one end of the loading groove 58, is disposed a cleaning lever 65 capable of pivoting freely, supported by a pivot 66 secured to the chassis 55. The cleaning lever 65 has a cleaning member 63 rotatably supported by a cleaner shaft 64. The cleaning member 63 is disposed at one end of the cleaning lever 65 by the side of the rotary drum 56, and at the other end thereof is fixedly inserted a pin 67. A connecting bar 68 is connected to the cleaning lever 65 by the pin 67. In the connecting bar 68, are formed elongated holes 69, 70 which are respectively guided by pins 71, 72 secured to the chassis 55. Further, as shown in FIG. 9, at an opposite end of the connecting bar 68 to the end where the cleaning lever 65 is connected, is formed an extended portion 68a which is adapted to contact the pole base 60 in an unloading state which will be described later. Furthermore, the connecting bar 68 is provided with a spring 73 whereby a force is applied thereto in a direction as indicated by an arrow N. Furthermore, at a position on the cleaning lever 65 at a vicinity of the loading groove 58, is formed a convex portion 65a which is adapted to contact with the pole base 60 having been shifted along the loading groove 58 in a loading operation which will be described later.
On the other hand, a cam 74 is installed on the undersurface of the chassis 55, located at a position opposite to the rotary drum 56, having the connecting bar 68 in-between. Further, in the undersurface of the chassis 55, is installed a transmission gear drive lever 75 which is engaged with the cam 74 through a pin 77. The transmission gear drive lever 75 capable of pivoting freely, is supported by a pivot 76 secured to the chassis 55. An end of the transmission gear drive lever 75 is connected to a loading transmission gear 79 by a pin 78. Moreover, as is also shown in FIG. 10, a loading gear 80 and further a loading gear 81 are connected to the loading transmission gear 79, and a lever 85 is connected to the loading gear 80 through a lever 82 while a lever 83 is connected to the loading gear 81 through a lever 84. The levers 83, 85 are connected to the respective pole bases 59, 60 by pins 86, 87.
Further, as shown in FIG. 11, on the surface of the chassis 55 is installed a cam 88 at the same location as the cam 74, and a drive lever 91 connected to the cam 88 by a pin 89 is supported by a pivot 90 secured to the chassis 55, being permitted to rock freely. An end of the drive lever 91 is connected to a half-load lever 93 through a pin 92. The half-load lever 93 is supported by a pivot 94, being permitted to rock freely so that a tape 96 can be guided by a half-load shaft 95 disposed on the half-load lever 93 in a fast forward operation or rewinding operation (half-loading) of the tape 96.
The following description will discuss the operation of the mechanism.
When there is no tape to be operated (unloading), the pole bases 59, 60 are located at unloading positions, namely, positions as is shown in FIG. 9. The connecting bar 68, having been shifted in a direction indicated by an arrow N' by being pressed at the extended portion 68a thereof by the pole base 60, is positioned at the N' side. As a result, the cleaning member 63 is located at a position away from the rotary drum 56.
When tape loading (hereinafter referred to as loading) is started, which is defined as an action to draw the tape 96 from a cassette case, not shown, and wrap it onto the rotary drum 56, the cam 74 is rotated in a direction indicated by an arrow L by a motor, not shown, and subsequently, the transmission gear drive lever 75 Pivots in a direction indicated by an arrow M on the pivot 76. Further, following the pivoting of the transmission gear drive lever 75, the loading transmission gear 79, loading gear 80 and loading gear 81 pivot. Following the pivoting of the loading gears 80 and 81, the respective levers 82, 85 as well as levers 84, 83 are shifted, whereby the pole bases 59, 60 are moved along the respective loading grooves 57, 58.
When the pole base 60 is moved, the connecting bar 68 is shifted in a direction indicated by the arrow N, guided along the elongated holes 69, 70 by the spring 73, as shown in FIG. 12. Thus, the cleaning lever 65 coupled to one end of the connecting bar 68 pivots around the pivot 66, whereby the cleaning member 63 comes into contact with the rotary drum 56. On the other hand, simultaneously with the start of loading, the rotary drum 56 rotates and magnetic heads installed inside the rotary drum 56 are cleaned by the cleaning member 63.
Further, when the pole bases 59, 60 have been shifted by the rotation of the cam 74, the pole base 60 comes into contact with the convex portion 65a of the cleaning lever 65 as shown in FIG. 9, and the cleaning member 63 separates from the rotary drum 56 again by the pivoting of the cleaning lever 65, thereby completing the cleaning operation.
Additionally, as to methods for permitting the pivoting of the cleaning lever 65, besides the above method for permitting it in accordance with the shifting of the pole base 60, another method may be taken wherein a solenoid or other device is employed.
Meanwhile, as shown in FIG. 13, the cleaner shaft 64 is disposed in a perpendicular direction to a reference plane of the rotary drum 56 such that the height at which the cleaning member 63 contacts with the rotary drum 56 is always kept constant.
However, in the above arrangement, since the cleaning member 63 always contacts with the rotary drum 56 at the constant height in cleaning operation, abrasion to the cleaning member 63 occurs unevenly. More specifically, since the abrasion occurs only at a portion thereof with which a magnetic head 97 contacts, an abrasion portion 98 is produced on the cleaning member 63 as is shown in FIG. 14. Therefore, the arrangement has a problem that a cleaning effect to the magnetic head 97 is reduced with operation time.
On the other hand, in the aforementioned arrangement wherein cleaning for magnetic heads is performed together with the loading operation, a problem is presented in that cost becomes higher; for example, in the case of operating the cleaning lever 65 by using a solenoid, it is necessary to provide an additional solenoid and driving circuit. Moreover, the arrangement shown in FIG. 9 also has problems that since it is necessary to provide the connecting bar 68 so as to shift the cleaning lever 65 in conjunction with the movement of the pole base 60, the number of parts is increased and larger space is required.